Want all the gain you can get and the earlier breakup of the JJ EL844's? This is our Low Output High Gain Option Retube Kit for the Dr. Z Mazerati. It contains a matched quad of JJ EL844's for power to drop the overall output a couple decibels, a JJ GZ34 rectifier tube, a handpicked High Gain JJ ECC83S for V1 and a current balanced 5751 for the phase inverter in V2.